[codex] add pnpm to project suggestions

[Sean-Kenneth-Doherty]

Summary

• add pnpm to the project suggestions list
• link the card to the pnpm GitHub contributor page
• include GitHub avatar, concise description, and package-manager tags

Validation

• GitHub API reports pnpm/pnpm is public, unarchived, and on main
• https://github.com/pnpm/pnpm/contribute returns HTTP 200
• https://avatars.githubusercontent.com/u/21320719?v=4 returns HTTP 200
• pnpm/pnpm has open good first issue-labeled issues
• pnpm source count is 1 via src/data/projects.js import
• git diff --check
• GITHUB_TOKEN=$(gh auth token) pnpm build
• generated dist/index.html contained the pnpm card and contributor link before restoring generated files

Addresses #1

[Sean-Kenneth-Doherty]

Validated locally on head 7e0c860ff54e9e2dacd525832f0643d1ff3a9642 in an isolated worktree:

• gh api repos/pnpm/pnpm --jq ... confirmed the repo is public, unarchived, and on main
• gh issue list --repo pnpm/pnpm --label "good first issue" --state open --limit 3 --json number,title --jq "length" returned 3
• imported src/data/projects.js and confirmed the pnpm source count is 1 with the expected contributor link and avatar
• curl -L returned HTTP 200 for https://github.com/pnpm/pnpm/contribute
• curl -L returned HTTP 200 for https://avatars.githubusercontent.com/u/21320719?v=4
• git diff --check origin/main...HEAD && git diff --check
• GITHUB_TOKEN=$(gh auth token) pnpm build
• checked generated dist/index.html before restoring generated files; the pnpm card is present and the contributor link appears once

All passed. gh pr checks reports no hosted checks on this branch.

[Sean-Kenneth-Doherty]

Closing this to reduce maintainer review noise from my project-suggestion-only PR batch. I am pruning these so the queue can focus on concrete bug, security, accessibility, and performance fixes.